Buggy code:
public class RythmEngine { public static final String version = "0.1" ; private final ILogger logger = Logger . get ( RythmEngine . class ) ; public Mode mode ; public final RythmProperties configuration = new RythmProperties ( ) ; public final TemplateResourceManager resourceManager = new TemplateResourceManager ( this ) ; public final TemplateClassCache classes = new TemplateClassCache ( this ) ; public TemplateClassLoader classLoader = null ; public IByteCodeHelper byteCodeHelper = null ; public IHotswapAgent hotswapAgent = null ; public IImplicitRenderArgProvider implicitRenderArgProvider = null ; private boolean refreshOnRender = true ; public boolean refreshOnRender ( ) { } public File tmpDir ; public File templateHome ; public File tagHome ; public FileFilter tagFileFilter ; public final List < IRythmListener > listeners = new ArrayList < IRythmListener > ( ) ; public void registerListener ( IRythmListener listener ) { } public void unregisterListener ( IRythmListener listener ) { } public void clearListener ( ) { } public final List < ITemplateClassEnhancer > templateClassEnhancers = new ArrayList < ITemplateClassEnhancer > ( ) ; public void registerTemplateClassEnhancer ( ITemplateClassEnhancer enhancer ) { } public void unregisterTemplateClassEnhancer ( ITemplateClassEnhancer enhancer ) { } public void clearTemplateClassEnhancer ( ) { } public RythmEngine ( File templateHome ) { } public RythmEngine ( File templateHome , File tagHome ) { } public RythmEngine ( Properties userConfiguration ) { } public RythmEngine ( ) { } public boolean isSingleton ( ) { } public boolean isProdMode ( ) { } private void setConf ( String key , Object val ) { } private void loadDefConf ( ) { } public void init ( ) { } @ SuppressWarnings ( "unchecked" ) public void init ( Properties conf ) { } public void loadTags ( File tagHome ) { } private void loadTags ( ) { } @ SuppressWarnings ( "unchecked" ) public ITemplate getTemplate ( File template , Object ... args ) { } @ SuppressWarnings ( "unchecked" ) public ITemplate getTemplate ( String template , Object ... args ) { } private String renderTemplate ( ITemplate t ) { } public String render ( String template , Object ... args ) { } public String renderStr ( String template , Object ... args ) { } @ SuppressWarnings ( "unchecked" ) public String renderString ( String template , Object ... args ) { } public String render ( File file , Object ... args ) { } public final Map < String , ITag > tags = new HashMap < String , ITag > ( ) ; public boolean isTag ( String name ) { } public boolean registerTag ( ITag tag ) { } public boolean registerTag ( String name , ITag tag ) { } public void invokeTag ( String name , ITemplate caller , ITag . ParameterList params , ITag . Body body ) { ITag tag = tags . get ( name ) ; if ( null == tag ) { resourceManager . tryLoadTag ( name ) ; tag = tags . get ( name ) ; if ( null == tag ) throw new NullPointerException ( ( "cannot<seq2seq4repair_space>find<seq2seq4repair_space>tag:<seq2seq4repair_space>" + name ) ) ; tag = ( ( ITag ) ( tag . cloneMe ( this , caller ) ) ) ; } else <START_BUG> if ( ( ( mode ) == ( Mode . dev ) ) && ( ! ( tag instanceof JavaTagBase ) ) ) { <END_BUG> String cn = tag . getClass ( ) . getName ( ) ; int pos = cn . lastIndexOf ( "v" ) ; if ( ( - 1 ) < pos ) cn = cn . substring ( 0 , pos ) ; TemplateClass tc = classes . getByClassName ( cn ) ; tag = ( ( ITag ) ( tc . asTemplate ( caller ) ) ) ; } if ( null != params ) { if ( tag instanceof JavaTagBase ) { ( ( JavaTagBase ) ( tag ) ) . setRenderArgs ( params ) ; } else { for ( int i = 0 ; i < ( params . size ( ) ) ; ++ i ) { ITag . Parameter param = params . get ( i ) ; if ( null != ( param . name ) ) tag . setRenderArg ( param . name , param . value ) ; else tag . setRenderArg ( i , param . value ) ; } } } if ( null != body ) tag . setRenderArg ( "_body" , body ) ; tag . call ( ) ; } private DialectManager dm_ = new DialectManager ( ) ; public DialectManager getDialectManager ( ) { } private ExtensionManager em_ = new ExtensionManager ( this ) ; public ExtensionManager getExtensionManager ( ) { } }

Fix:
if ( ! ( tag instanceof JavaTagBase ) ) {